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SS 316 High performance fittings > Pipe fittings > Overview

  Pipe Fittings and Adapters
Pipe Fittings & Adapters have two primary functions. They can either be used for sealing fluid within a hydraulic system, and/or they can be used for mechanically joining components.
In order to understand how Pipe Fittings & Adapters perform in these two roles, you should have a basic understanding of how they make a seal. Pipe Fittings & Adapters seal in one of four ways:
• Generating torque which seals tapered male and female threads together, or
• Compressing an o-ring between machined surfaces on the components being joined or sealed, or
• Seating a 30° angle on a female gland to a seat on a mating male tapered thread, or
• Using heat to permanently weld or braze the hydraulic system components together.
Tapered Pipe Fittings rely on the stress generated by forcing the tapered ends of the male half of the fitting into the female half of the component or port.
Straight Thread Adapters seat an o-ring on the shoulder of the male half of the connector against a metal sealing surface on the female port
Pipe Swivels connect a 30° cone inside a straight pipe thread female swivel to a 30° tapered seat on the end of some male pipe thread fittings.
Weld & Braze Adapters seal after heat and a filler material is used to permanently bond tubing or pipe to an adapter. Sealing occurs after butting the two parts together (butt welding), or inserting pipe or tube into a socket in the adapter (socket welding or brazing).
Koncentrik Unions join pipe or tubing. Metal-to-metal contact between mating taper angles in the union is reinforced by a fully confined Teflon seal to form a leak-proof joint.
Pipe Fittings & Adapters
Feature Threaded-Tapered Threaded-Straight Pipe swivel Weld & braze Koncentrik
Pressures Very high to 7,200 psi (static systems only) High to 6,000 psi High to 6,000 psi Very high to 12,000psi Very high to 10,000 psi
Temperatures Stainless: -425° to 1200°F Nitrile/Buna: -30° to 250°F Stainless: -425° to 1200°F Stainless: -425° to PTFE/Teflon: -100° to
Brass: -40° to 400°F Viton: -15° to 400°F 1200°F 450°F
Monel: -65° to 800°F Monel: -65° to 800°F
Vibration Poor Very Good Medium Excellent Very Good
Materials SS 316/SS 316L stainless steel SS 316/SS 316L stainless SS 316/SS 316L stainless SS 316L stainless SS 316/SS 316L stainless
M405 Monel M405 Monel M405 Monel
CA377/CA360/CA345 brass
Size Available 1/8" – 2" #4 - #32 #4 - #32 1/8” – 2” 1/8” – 2”
(nominal) #4 - #32
Seal Reliability Good in static systems Excellent in static systems; Good in static & dynamic systems. Excellent. Very good
Poor in dynamic systems Very good in dynamic systems Low tolerance to damage Permanently brazed or PTFE seal reinforced
Medium tolerance to minor Medium tolerance to thread along sealing angles. welded joints are by metal-to-metal seal
thread imperfections & taper angle imperfections Medium tolerance to leak-free & high Medium tolerance to
Medium tolerance to   thread imperfections. resistant to vibration. surface imperfections
assembly variation   Medium tolerance to assembly
variation like
Thread & Port Anaerobic sealant or thread General lubricant applied to General lubricant applied Fluxing & other prep. Varies. Connects to
Preparation tape threads to threads Steps required for tubing, pipe & port
weld connections.
Ease of Medium Very high Medium. Difficult. Medium.
Assembly L1 thread gauge & basic Intuitive make-up Flats from Finger-Tight Certified welding or Flats from Finger-Tight
ass’y practices must be Simple process method utilized. brazing skills method utilized.
followed required.
Ease of Limited breaks and remakes Very good. Virtually Good. Low metal N/A. Permanently Very good. High
Maintenance due to metal deformation of unlimited breaks & deformation to create seal assembled joint number of breaks &
threads remakes. O-ring means moderately high cannot be maintained. remakes with Teflon
replacement only repeatability snap-ring
Specification J514, MIL-F-18866 SAE 1926, ISO 11926 SAE J514 ANSI B31.3 ANSI B31.1.0 Power
Conformance ANSI B1.20.1, JIS B0203, UN/UNF/UNEF: ANSI B1.1, ANSI B1.20.1 Piping
(design & thread) BS 21, ISO 7/1 ISO 263 ANSI B16.11 Forged
BSPP: ISO 228/1, BS 2779, Steel Fittings Socket
DIN 259, JIS B0202 Welded & Threaded